Hazy Al2O3-FTO Nanocomposites: A Comparative Study with FTO-Based Nanocomposites Integrating ZnO and S:TiO2 Nanostructures

In this study, we report the use of Al2O3 nanoparticles in combination with fluorine doped tin oxide (F:SnO2, aka FTO) thin films to form hazy Al2O3-FTO nanocomposites. In comparison to previously reported FTO-based nanocomposites integrating ZnO and sulfur doped TiO2 (S:TiO2) nanoparticles (i.e., ZnO-FTO and S:TiO2-FTO nanocomposites), the newly developed Al2O3-FTO nanocomposites show medium haze factor H-T of about 30%, while they exhibit the least loss in total transmittance T-tot. In addition, Al2O3-FTO nanocomposites present a low fraction of large-sized nanoparticle agglomerates with equivalent radius r(eq) > 1 mu m; effectively 90% of the nanoparticle agglomerates show r(eq) < 750 nm. The smaller feature size in Al2O3-FTO nanocomposites, as compared to ZnO-FTO and S:TiO2-FTO nanocomposites, makes them more suitable for applications that are sensitive to roughness and large-sized features. With the help of a simple optical model developed in this work, we have simulated the optical scattering by a single nanoparticle agglomerate characterized by bottom radius r(0), top radius r(1), and height h. It is found that r(0) is the main factor affecting the H-T(lambda), which indicates that the haze factor of Al2O3-FTO and related FTO nanocomposites is mainly determined by the total surface coverage of all the nanoparticle agglomerates present.